1.  less than Field of the Invention greater than 
The present invention relates to a calcium channel antagonist capable of inhibiting intrusion of calcium into cells which possesses an inhibitory action against secretion of parathyroid hormones, an agent (a medicament) for promoting absorption and utlization of calcium into human body as well as a process for preparing the antagonist and the agent and also to a calcium preparation wherein a calcium material has been incorporated with the calcium channel antagonist for enhancing effective utilization of the calcium value. More particularly, the present invention relate to a calcium channel antagonist possessing an inhibitory action against secretion of parathyroid hormones which comprises an acid extract of a calciferous (calcium-containing) material of plant origin baked in a specific manner, an agent (medicament) for promoting absorption and utilization of calcium as well as a process for preparation thereof, and a calcium preparation wherein a known calcium preparation has been incorporated with the calcium channel antagonist.
As is evident from the foregoing description, the calcium channel antagonist of the present invention is effective as a single substance for attaining dual purpose of inhibiting secretion of parathyroid hormones and promoting absorption and utilization of calcium in human body.
2.  less than Description of the Prior Art greater than 
It is well recognized that calcium is one of the indispensable constituents for the formation of bones and teeth of mammalia including human. In recent years, it has become manifested, not only the above recognition, that calcium is one of the most important nutritive substances sustaining all of the living phenomena. Accordingly, calcium is now being watched among research staffs in the far front of the medical field.
As an example of this fact, a variety of studies on calcium paradox are reported under the title of xe2x80x9cContact Point of Dietetics with Cytobiologyxe2x80x9d in a Japanese magazine entitled xe2x80x9cClinical Calciumxe2x80x9d, Special Edition, xe2x80x98Calcium Paradoxxe2x80x99, January 1996 published by Medicinal Journal Co.
According to these medical articles, a great number of functions attained by calcium in human body have been made clear. Above all, a key of human health has now become impossible to consider without the relation between calcium and parathyroid hormones.
Reported heretofore is that the living action of human including digestion, absorption and excretion of foods; synthesis and internal secretion of hormones; immunization mechanism; function of looking at everything; function of thinking about everything; and other all functions depends on the action of calcium in such manner that all of the cells are controlled by the signal (information) emitted from calcium in blood and working of heart and brain is caused by the action of calcium.
According to this report, it is necessary that the concentration of calcium in blood has to be maintained at all times at a definite level in order that cells may function normally. It has also been made clear that a difference in concentration of calcium between the inside and outside of cells (in blood) has to be maintained at about 1:10,000.
To say it in another way, the concentration of calcium inside cells has to be kept at 1/10,000 of that outside cells in order that the signal emitted from calcium may correctly be caught. So far as the difference in concentration is kept, the individual cells can act their rolls according to the correctly transmitted information.
In case the concentration of calcium in blood is decreased, working of heart and brain will be ceased to cause death. In order to prevent such deleterious or rather fatal result, human body is naturally designed to have parathyroid hormones worked for dissolving calcium from bones into blood to maintain life. In human body, 99% of calcium is stored in bones. If dissolution of calcium from bones continues and goes too far, solid bones will become spongy to cause osteoporosis. What is more, continuous dissolution of calcium incurs a detrimental influence on human body in that although action of heart is not ceased and life is thus maintained by augmenting blood with calcium, excess calcium brought over in cells by internal secretion of parathyroid hormones incurs considerable overbalance of calcium concentration inside and outside the cells, thus disturbing intercellular transmission of information to lose normal action of the cells. This phenomenon is called calcium paradox which is a disease caused by a series of phenomena; (I) shortage of calcium, (II) depression of calcium concentration in blood, and (III) secretion of parathyroid hormones capable of increasing calcium in cells. This calcium paradox exhibits the following symptoms: headache, dementia, cataract, anemia, hypertension/apoplexy, deafness, hypotension, stiff shoulder, immunodeficiency, osteoporosis, stress, arterosclerosis/cardiac infarctio, gastric ulcer, duodenal ulcer, infectios disease/cold, pneumonia, cancer, allergy/atopy, renal calculus, prostatomegaly, weak nail, hepatitis/cirrhosis, neuralgia, chronic articular rheumatism, and arthritis
By increase of calcium in cells is meant that the cells get ill and go to aging. If calcium is continuously increased, cells sustaining life will decease, inducing death of human life as a matter of course.
For human body consisting of about 60 trillion cells, calcium is one of the indispensable nutrients sustaining not only bones but also living action of all tissues including heart and brain and always has to be supplemented externally as an important nutritive component lest it should become short.
Notwithstanding calcium is such an important nutritive component, it is a current status that our dietary life is recently dependent on processed foods and our intake ratio of calcium is not said to be sufficient.
In the event foods is short of calcium, the content of calcium in body becomes smaller and moreover a balance of calcium saved at a definite rate in cells, blood, and bones will be lost so that the aforesaid considerable status for human body will be incurred.
A preferable ratio of calcium existing in cells, blood and bones is said to be about 1:10,000:100,000,000. Calcium existing in such ratio in cells, blood and bones displays respectively the following behavior:
The actions of calcium in cells are: (i) sustaining whatever actions in cells and receiving information, and (ii) causing cleavage, multiplication, movement, secretion, excitement, and metabolism of cells.
In blood, calcium exists in an amount of 10,000 times of the cells and displays the following behavior: (i) activating heart and brain, controlling the action of cells and receiving information; (ii) transporting calcium everywhere in body, and (iii) maintaining calcium in blood at all time at a definite concentration.
A calcium value saved in bones occupies 99% of the total calcium and displays the following behavior: (i) supporting body and making bones strong, and (ii) in case of the calcium concentration in blood being decreased, dissolving calcium from bones by the aid of parathyroid hormones thereby supplementing the lacked portion and maintaining calcium in blood at a definite concentration.
 less than Problems to be Solved by the Invention greater than 
As is understood from the foregoing, if calcium in an amount sufficient enough to maintain calcium in blood at a definite concentration is at all times supplemented externally, secretion of parathyroid hormones fails to take place so that calcium is not increased in cells to ensure that all of the functions in human body act normally.
According to the recent study, an amount of calcium daily necessary for adult is reported as 800 mg. Noteworthy here is, however, that all of the calcium contained in foods and drinks is not absorbed in human body. It has now been made clear that the calcium content usually designated for foods and drinks is greatly different from the amount of calcium actually absorbed in human body. It follows that if a necessary amount of calcium is to be taken from daily meals, an enormous amount of calciferous foods will have to be taken.
For example, a calcium content of milk known as a drink containing a high unit of calcium is at most about 100 mg/100 ml. As the calcium contained in milk is combined with proteins, its absorbability is said to be good. However, absorption rate of calcium for human body is 50% in maximum, i.e. only 50 mg of calcium is absorbable per 100 ml of milk. Furthermore, proteins present in milk as a combined state with calcium are digested, absorbed and finally converted into acids such as lactic acid, butyric acid, pyruvic acid, sulfuric acid, and phosphoric acid so that a majority of the aforesaid 50 mg of calcium may be consumed to neutralize these acids. Thus, notice has to be paid to a report that a calcium value in 100 ml of milk absorbed in human body may actually be at most about 20 mg. It is a matter of course, therefore, that a necessary amount of calcium cannot be supplemented only with milk. In case an insufficient amount of calcium is to be supplemented with other food and drinks, the amount of calcium contained in such foods and drinks, even in case of dried sardines, fresh sardines, hijiki (Hijikiaf fucalesxe2x80x94a kind of sea weed), and baked laver are known as calcium-enriched foods, is smaller and utterly fails to reach the above mentioned daily necessary amount. After all, it is a current status that intake of a necessary amount of calcium is rather hard from usual meals. Consequently, we gradually fall in the state of chronic short of calcium, thus incurring a recurring phenomena of decrease in calcium concentration in blood, secretion of parathyroid hormones for compensation of the decreased amount of calcium, and a continuous dissolution of calcium from bones causing the aforesaid various diseases.
Such status is not limited to our country, especially in view of the fact that even in European and American countries where consumption of milk is said to be 3-5 times as much as our country, osteoporosis patients caused by short of calcium in these countries are twice in number as compared with those in our country. In view of this fact, it will easily be understood that solution of the problem of calcium deficiency is impossible only by intake of a calcium-enriched foods and drinks such as milk.
As for Vitamin D known as promoting absorption of calcium, this vitamin can be formed by sunlight irradiation of a provitamin D in body or can be taken from foods. Vitamin D is converted by the aid of liver or kidney into an active type Vitamin D which assists absorption of calcium through intestine. However, this function is extremely decreased as aging proceeds. Further, intake of synthetic active type Vitamin D brings about a problem as it accompanies a considerable side-effect of causing hypercalcemia, uremia, and osteomalacia.
Accordingly, it is an object of the present invention to provide a calcium channel antagonist capable of inhibiting secretion of parathyroid hormones and intrusion of calcium into cells, and simultaneously effective for promoting absorption and utilization of calcium, as well as a process for preparing same.
It is another object of the present invention to provide a calcium preparation capable of being added to calcium or conventional calcium preparations, which preparation can be enhanced in absorption efficiency of calcium without assistance of Vitamin D, any athletic movement and irradiation of sunlight and is effective for the formation of bones without exhibiting any side-effect because of its extremely high in vivo utilization efficiency (or bioavailability) of absorbed calcium.